I’m typically a heavier driver. In my proudest moment, I ran a full league season against our strongest class of drivers, starting at 30lbs over the weigh in, and miraculously won the season. That was truly amazing because at least 3 of the drivers were ranked in the top 20 US indoor karters at the time. Mind you, I went on a keto diet the night we started the 8 week race season and finished my last race at legal weight, but for 7 of those races, I was over the weigh in.
Anyone with any karting experience knows that even just a difference of 10lbs will essentially rob you of about 0.015 of a second per corner. While that’s not much, it adds up when you have like 6 to 10 corners to deal with. And it really adds up when you’re at like 210lbs racing against a 180lb driver. We had 7 corners in our series so I was running at a 7×0.015 x3= 0.315 second handicap per lap. And our races are 50 laps long!
So how did I pull that off?
Well let’s look at how extra weight in a go kart causes problems and what you can do about those problems.
The problem is acceleration zones and corners. Without getting too scientific about it, basically Newton’s laws of kinetic energy are working against us.
(Stuff it, I have to give you formula, K=mv^2/2. Kinetic Energy = Mass x Velocity squared, divided by 2. This formula tells us how much energy is required to reach any speed.)
The problem is that to reach the same velocity a heavier driver requires the engine to deliver more energy than a lighter driver requires, and the engine can only deliver the same amount of horsepower per second to both drivers. The lighter driver has a serious acceleration advantage. And that means the lighter driver can slide around and will be forgiven. You, the heavier driver, will not be forgiven for a slide.
But fear not, most drivers have no idea what makes a kart slow or fast, and so make loads of mistakes. Your job as a heavier driver is to not make those mistakes, and to approach it with advanced knowledge of your machine and how it works, so you can drive it with control and purpose.
So tip #1 . DO NOT SLIDE!
That means you have to be very accurate with your turn in timing. You need to have very clear marked out turn in points, and you need to hit them with absolute precision, every time. One way to work this out, is to walk the track and find marks and angles from the outside of the track to the apex. You want about a 45 degree turn in point to the apex. Mike Smith the US national indoor karting champ (of 2007 I think) would stand at the apex then count the steps to measure the width of the track. Then he would turn 90 degrees and walk back down the track the same number of steps, then turn around and his foot would be at 45 degrees to the apex. That was his turn in point. At least the starting turn in point from which he would adjust according to how his kart handled.
The way I handled the problem was I got a go pro and I captured my fastest laps from a helmet cam. Then I went home and studied my fastest laps in slow motion and worked out exactly what happened, where I turned in, where I exited. And I took note of marks on the track that lined up with my wheels. Then I could go out and hit those marks every single time.
So Tip #2. Get a helmet cam and study your fast laps in slow motion.
One of the other reasons people slide is that they are not steady with their hands in a turn. A big part of being steady is just getting your turn in timing right, but it is also making the conscious decision that you are going to go through turns using as little hand movement as you possibly can, once you’re loaded up and going through the turn. You might need to fiddle about a bit on your turn in to catch your balance, but your ultimate goal is to get smooth and steady and to not be wobbling your hands around like you’re trying to counter steer every little bump and slide. I see many beginners driving what I call nautical miles. Like they’re trying to drive over the waves of the ocean. You can literally see the front wheels of their karts flapping left and right as they go through a turn. Don’t do that.
Tip #3, Aim to keep your hands steady and fixed through the greater part of the turn. Do not wobble the steering wheel all through the turn.
Now the best way I have found to achieve this, steady hands and steady front wheels, is to first realize that you actually have full visible access to those front wheels. This is not like a car where you can’t see where your wheels are pointing. A kart is more like a formula one car, you can see where the wheels are pointing! I can’t stress enough how important that is, you need to use this to your advantage.
What you do is put your eye directly on the apex, with the intention of aiming your front wheels right at that apex so you can get as close to it as possible. Remember your goal is not to try and use steering tricks to counter sliding through a turn. Your goal is to have no sliding and just flow through the turn under a steady G force.
So this gives several tips.
Tip #4. Put your eye on the apex as early as possible from way up on the straight, not as you turn in (that’s too late).
You need your eyes on apex early, when you are back on the straights. Looking at the apex too late is the major reason for people missing the apex.
Tip #5. Watch where your front wheels are pointing through the corner of your eye, (while your eyes are on the apex). Then just deliberately point your wheels at the apex, making the minimal adjustment needed to keep them pointed.
When you do this you become very smooth and consistent. You will find you are able to approach corners faster because you don’t break loose as easy or as often. So you don’t need to slow down as much for turns.
Tip #6. Always try to get your kart as close as possible to the apex, every time.
The reason for always being as close as possible is that any distance at all off the apex, makes the track longer. There is pretty much NEVER any speed advantage to being off the apex, and there is pretty much a 100% chance that you’ve made the track longer. How much longer? Well consider a 180 degree turn, if you are 2 feet off an apex, then you have to travel 2 feet further down the approaching straight. Now you have 2 extra feet to travel to get back on line as you go down the exit straight. That 2 feet off the apex, cost you 4 feet of track length, with no advantage in speed. This is probably the number one reason that races are won and lost, the fastest drivers are actually driving a shorter track, while going the exact same speed. So while you still need to get out wide for most turns, in an indoor kart situation you need to be looking at how you can make your turns just slightly tighter than your opponents, without losing traction.
Next we will talk about ‘the bind’, and how it can effect heavy drivers.
Now one of the major problems for a heavy driver, is that an indoor kart has a solid rear axle. This means that both rear tires travel at the same rotational velocity at ALL times. That means that the rear wheels when both firmly planted on the ground want to push the kart in a straight line at all times, even when you turn the steering into a turn. If you try to turn the steering wheel and push a kart in the pit, you’ll see what I mean, it’s like the brakes are jammed on, it doesn’t want to roll. This is known as binding, and it is a major loss of momentum energy. When you turn the wheel the front wheels and the rear wheels go into a fight, and if all 4 wheels are planted down flat and hard, unless the rear has lost traction, the front wheels are going to lose the battle.
This describes what happens when a kart is “pushing”. It also describes what happens to a kart when it slides, because essentially the outside rear tires have lost grip. The loss of grip causes the inside rear tire to slam down, because there is nothing resisting the lateral inertia. And so a kart that has just slid, has totally lost it’s geometric advantage, which I will describe now.
Now the kart is actually designed to deal with the solid rear axle problem by setting the front steering geometry up in a way that causes the kart to twist and tip over when you turn the steering wheel. Kind of. The inside rear wheel (when you are decelerating) lifts off the ground when you turn the steering wheel. So a properly functioning and operated kart is actually on 3 wheels through a turn. One back wheel on the outside, and two front wheels. In this case the solid rear axle, is no problem, the inside wheel just spins in the air. This works best when you are decelerating into a turn.
But if you are accelerating out of a slow turn, that rear wheel is much less likely to lift off the ground, because it does not have the forward weight bias to push the front wheels down and lift the rear wheels. This means that a heavier driver is more subject to an effect that we call ‘the bind’. The bind is where the weight bias due to the effect of acceleration is pushing the rear wheel down before it gets a chance to develop lateral inertia (the sidewards G force you feel in the middle of a turn). The heavy driver is extremely handicapped by the bind, much more so than a lighter driver will be.
So here’s the answer to the binding problem when under acceleration. You have to learn how to, violently and rapidly snap at the wheel when you begin your turn in. The pro drivers call this, ‘the snap in’ technique. It can be achieved in several ways, one way is similar to ‘the Scandinavian flick’ a trick that is used by rally drivers where you kind of initially turn away from the turn to load your weight onto the inside before turning back into the turn to cause the weight to aggressively transfer to the outside of the vehicle. This works best when there is a lot of traction on your track say from built up rubber and the bind is out of control. My preferred method is to over turn the steering wheel on initial entry with a very fast snap at the wheel, and then to release that pressure half way, and then return to a steady mid point. In timing it’s about 1/2 a second total from 1. snap in, 2. recoil, 3. aim at the apex and hold. If you can imagine the weight jarring quickly from one side to the other, which tips the kart up onto 3 wheels, and now you have to catch the momentum or things will get out of control. Mind you, the Snap In is NOT for corners that you are approaching quickly and decelerating into because there is no need to worry about binding in these situations. You should always be on the alert for situations that are causing binding, and thinking about how you an tip the kart over to deal with it.
So Tip #7, learn how to snap at the wheel when you’re accelerating into a turn, in order to tip the kart over sideways onto 3 wheels. This will give the heavier driver roll speed that he would not normally have due to his binding handicap.
Now there is another place where the bind can happen, and that’s on the exit as you accelerate out of a turn. If you have not achieved a 3 wheel tripod effect, then you’re going to bind your exit. You’re going to have to analyze your weight transfer and listen to your engine to know if you’re in this situation because different things can cause it, and it’s not always easy to realize you’re binding on an exit. But lets talk about some of the things that can cause it. Of course the usual culprit is that you’ve slid the rear out, ever so slightly, and you’re slipping a little as you start the exit. It’s hard to catch yourself doing this. But as general rule, the cause is from getting on the gas too early. Well that’s the easy fix, just coast more, and get on the gas later.
When you coast through a turn you maintain the 3 wheel tripod so much easier, and we call this ‘roll speed’. So you should really practice this first because it is very fast. But, it’s not the fastest way to get through the turn, and as a heavier driver trying to beat a lighter driver, now I’m going to tell you something that breaks this rule. But really, you need to master the coasting technique first.
Okay, so the reason we are binding our exit acceleration in the last example is because we are sliding ever so slightly, because we pushed for too much acceleration too early. The problem with pushing for acceleration too early is that the forward weight bias that is created by a deceleration into a turn has not had the chance to settle and return the weight bias to middle or rear. So the back is light and does not yet have adequate down force to accelerate through and out of the turn. This is why we coast, we are waiting for the forward weight bias to return to an equilibrium. But here is the thing, when you are in a turn there are actually many things that will cause the weight to shift forward and rear quicker or slower. For example if you were to hold the brake down longer and deeper, then the weight will stay forward biased longer. If you brake for a shorter distance, then the weight will stay forward biased longer, because you will throw more inertia towards the front of the kart. As opposed to say if you extended your braking distance by say just 3 more feet earlier. You see the weight transition would be smoother and more gradual. That would actually allow you to trail brake into the turn and load the front wheels up more carefully. That actually allows you to roll through the corner more quickly and ultimately it allows the weight bias to return to equilibrium sooner.
So that’s one way, don’t slam the brake hard at the last split second. Think about how that’s going to effect your weight transfer and loads and traction. Your goal under high loads is to smooth and slow the weight transitions.
As another example, now when you turn the steering wheel into a turn, those front wheels act a bit like brakes, ever so slightly, the turning is causing the weight bias to push towards the front of the kart. Now if you release the turn in, the weight bias will gently release back to the rear of the kart. Or at least to the middle. It ever so slightly releases forward weight pressure. That means if you release your steering pressure, just before you begin accelerating, you get a rear downforce bonus at the split second you release steering. That means you dont get the little slide that breaks you loose, and you get to get back on the gas earlier than if you waited and held your steering steady. The trick is that once you have acceleration started, you reapply the steering pressure that you had initially. Do you get it? We call it the 1-2-3 because it kind of happens in a 3 phase process, again it all happens in a split second, maybe a second at most. The acceleration rate by the way is not usually a stomp it’s a squeeze, so you don’t induce slide.
so Tip #8, learn to release steering pressure ever so slightly before you accelerate, and then squeeze the gas and reapply steering pressure. This allows earlier acceleration without sliding.
Now if you understand what we just did, then you’ll understand the next thing I’ll explain to you. Notice that we just caused the rear downforce to return to our rear a little bit sooner by releasing the steering before we accelerated. But there are other more aggressive ways to do this too. I should mention here that the reason we need to have all kinds of different methods is that in a rental kart scene, we have all kinds of different broken karts. Some karts you have to be very gentle with, others you can do aggressive things to them and they’ll grip up for you. You have to feel your way, and adapt as conditions change and tires temps and pressures change.
So the final expert advanced method to induce an early rear down force is to double blip and even triple blip the gas before acceleration. Now this is my favorite trick because it lets me get full throttle way way earlier than normal. As much 6 to 8 feet earlier, and that means your acceleration time and straight length is much longer. This allows a heavier driver to compete with lighter drivers but you have to be very careful not to overdo it and slide anywhere. You are really going to be on the edge here. So I’ll explain what I believe is happening here. You’ll typically see the apex about a kart length to a kart and half in front of you when you start this move. And normally say with a coasting technique, you can’t touch the gas until the front of the kart has reached the apex. You begin by blipping the gas briefly. Now if you were to hold it down, you would slide out for sure. But you don’t hold it, you just go blip(1), release(2), squeeze(3). The whole 3 moves are done in about one second timing. The actual timing you will learn to be able to feel. You’ll actually become sensitive to the weight transition to the rear during the first blip. I can feel it as an increase and change in the feeling of the seat against my back. As that pressure increases I start to squeeze the gas. That first blip throws the weight to the rear, but because we release the gas, the tires just down force and grip up. Now you can squeeze on the power with traction and power out. Be very careful not to slide though, because if you do, you bind, and then any acceleration bonus is cancelled out.
Tip #9, Learn to double blip the gas before accelerating and you’ll be able to start accelerating a kart length earlier than normal, without sliding.
Now we have talked a lot about binding being caused by the dragging of the inside wheels. And here we are talking mainly about indoor karts, which have thick strong chassis’, and are much less flexible than outdoor karts. There is another trick that helps with indoor karts which involves using your heavier weight and strength to your advantage. Basically when entering a corner, you have to push your heal in against the base of the stirrup towards the inside of the turn. So if you are turning left you push your left heal down towards the turn. And likewise if you are turning right, you push your right heal down. What you are trying to achieve is cross tension across the frame. It’s a bit hard to explain why this works, but basically it assists that inside rear wheel to lift off the ground and assists your kart to roll through turns with extra downforce in the places that it is needed. If you do this while on a set of scales in an outdoor kart, you can see the wheel weights change as much as 20lbs from left to right. You have to push fairly hard. It’s pretty unnatural to do this, so it takes some practice but it can really help with karts that are broken and twisted, particularly karts that push and are bound up. For a heavier driver that can be bound up through sweeper turns, pushing in with your heal to twist the chassis can make a huge difference to roll speeds. If you think a bit about what it does, you’ll realize why. Imagine you are pushing with your left heal, and you pushed the front left wheel down on a left hand turn. That would cause the outside rear wheel to push down, and inside rear wheel to lift up. That’s what cross tension does.
Tip #10, Learn to use your heals to create cross tension across the kart.
Now being a heavier driver it is very important how you distribute your body weight in the kart. In short, you have to LEAN OUT of the turns, DO NOT LEAN INTO TURNS. This is so super critical it can’t be over stressed, it should probably be lesson and rule #1. To explain, it goes back again to that solid rear axle, but it also relates to the direction of down force and lateral force on your wheels. Remember that solid rear axle requires us to lift up the inside rear wheel. Otherwise you bind up as the inside rear wheel drags. So it follows that leaning outwards will lighten the load on that inside rear wheel. A 200lb person can easily shift 50lbs from one rear wheel to the other, even if the wheel doesn’t lift off the ground. But now we have to also consider the angle of the lateral forces from that weight. It’s best explained with an image. If you are leaning out then the angle of force on the rear outside tire is more downwards, which promotes traction. But if you are leaning inwards then the angle of the force is more outwards than downwards, in this case you are inviting the kart to slide out. Drivers who lean into turns, are more loose and prone to slide, and then they bind up. Drivers who lean out, have more traction and therefore less slide and are less likely to bind up. It takes some practice to get used to leaning out, because you have to resist the urge to fight inertia, but once you have it down, it’s very natural. Note also that when you lean out of a turn you DO NOT LEAN OUT WHEN YOU ARE IN THE TURN, LEAN OUT WELL BEFORE THE TURN IN, WHEN YOU ARE ON THE STRAIGHT.
Tip #11. Lean OUT of turns, DO NOT LEAN INTO TURNS!!!! IMPORTANT.
My last idea is to be very mindful of how the weight transfers from front to rear when you release the gas from full throttle. This is important for sweeper turns, or fast turns where you basically enter at top speed and hope to fly through. Often in these turns you find the kart going into a slide at the apex and just not able to hold full throttle through the whole turn.
The slide we are talking about here is known as ‘snap oversteer’. It is caused mainly by the shift in weight from the rear to the front as you get off the gas while you are at maximum inertial load in the middle of turn. The release of gas lightens the rear and back goes into a drift.
In these cases people usually get off the gas WAY WAY too late. It seems counter intuitive, but you usually have to get off the gas way early, WHEN YOU ARE ON THE STRAIGHT or just ever so slightly after turn in. That seems way early, you have no risk at all of sliding on the straight, what gives? The reason is that releasing on the straight causes the weight to shift forward BEFORE the turn in. As the front wheels bite down and you start the turn in you can now reapply the gas, and you can stomp down fast and hard. The whole kart geometry has changed from being flat biased in the rear with a middle biased center of gravity, to lifting the inside wheel and establishing the correct 3 wheel bias for roll speed, the slight drop in velocity on entry tips the kart forward and over as you turn in. Now if you have leaned out correctly and early, and you are pushing in with your inside heel, the center of gravity will create downforce and grip on the outside wheels. Now you can push full throttle through the whole turn with no risk of sliding and no need to release the throttle. Again your eye is on the apex, and you are aiming your front wheels with a steady hold of the wheel. Sections like this are usually where I pick up a lot of time on other drivers as I watch them lose traction every time they lift up.
Tip #12. If you are sliding pr binding in a turn that should be taken at full throttle, blip off the gas, when on the straight, just before turning in. Blipping off the gas creates forward bite and tips the kart over, releasing bind. This increases roll speed, and traction.
The trick is to be very mindful about how shifts in the weight are caused by getting on and off gas, or by steering input, and how these might create slides when at full loads, and then to think about what kind of geometry might be in play at that time. Then you can think about what you can do to change the geometry and weight distribution in advance. You will find that things like trying to make adjustments to your body position when you are in a turn already is probably too late. Note also that many of these tips involve manipulating the weight transfers to give you the ability to hold the gas down full when normally you cant.
These are actually not only tips for heavy drivers, they’re tips for any driver. The good thing is that lighter drivers are usually not effected by bind and sliding as much, so they don’t work on it as much. But for heavy drivers, getting these things perfect are really your only hope of evening the odds. The good thing is that when race time comes and ballast is added you will dominate your weight class.